File photo of the Pentagon.
US forces staging the first strikes against Islamic State jihadists in Syria also targeted a separate extremist group plotting an imminent attack against US and Western forces, the Pentagon said.
In the air strikes against IS jihadists, the US was aided by Arab allies Bahrain, Jordan, Saudi Arabia, Qatar and the United Arab Emirates, it said.
Eight US air strikes were also aimed at the hardline Khorasan Group which is made up of former Al Qaeda operatives, the Pentagon said in a statement.
"The United States has also taken action to disrupt the imminent attack plotting against the United States and Western interests conducted by a network of seasoned Al-Qaeda veterans, sometimes referred to as the Khorasan Group, who have established a safe haven in Syria to develop external attacks, construct and test improvised explosive devices and recruit Westerners to conduct operations," the statement said.
"All aircraft safely exited the strike areas," it added.
The US side of the attack featured a mix of fighter, bomber, remotely piloted aircraft and Tomahawk Land Attack Missiles to conduct 14 strikes against IS, which is also known as ISIL.
"The strikes destroyed or damaged multiple ISIL targets and included ISIL fighters, training compounds, headquarters and command and control facilities, storage facilities, a finance centre, supply trucks and armed vehicles," the statement said.
A total of 47 Tomahawk missiles were fired by US ships in the Red Sea and the North Arabian Gulf.